Rim tape shields an inner tube from spoke ends, sharp metal edges and holes in the rim. It must securely cover every spoke hole. Tape that is too narrow can move aside, making a tire change a useful opportunity to inspect this small component.
In a tubeless wheel, the inside of the rim must be airtight. Suitable adhesive tape conforms to the rim surface and resists tire sealant; ordinary adhesive tape is not automatically suitable. The valve also needs an airtight seal. Tape alone cannot make an incompatible rim and tire suitable for tubeless use.
The photograph shows tube-protection tape being fitted. When choosing a replacement, check the rim manufacturer’s requirements for tape type and width. A tube system needs uninterrupted protection over the spoke holes; a tubeless system also needs an airtight barrier. Before refitting the tire, inspect the tape for damage or displacement.